The spacecraft is at the end of a three-year mission that scanned the lunar surface from orbit and tested a new, efficient, ion-propulsion system that officials hope to use on future interplanetary missions.

Launched into Earth's orbit by an Ariane-5 booster rocket from Kourou, French Guiana, in September 2003, SMART-1 used its ion engine to slowly raise its orbit over 14 months until the moon's gravity grabbed it.

The engine, which uses electricity from the craft's solar panels to produce a stream of charged particles called ions, generates only small amounts of thrust but only needed 80 kilograms (176 pounds) of xenon fuel.

The craft's X-ray and infrared spectrometers have gathered information about the moon's geology that scientists hope will advance their knowledge about how the moon's surface evolved and test theories about how the moon came into being.

In a scare on Saturday, mission officials said they had to raise the low point of the spacecraft's orbit by 600 metres (2,000 feet) by using its positioning thrusters to avoid the 1.5 kilometre-high (almost mile-high) rim of a lunar crater.

Had the orbit not been raised the craft would have crashed one orbit too soon, making the impact difficult or impossible to observe.